Cream together butter and sugars until light and fluffy. Add egg, and beat well. Add in peanut butter and vanilla, mixing well.
Sift together flour, baking soda, and salt. Stir dry ingredients and oats gradually into creamed mixture. Spread mixture into a greased 13x9x2 pan. Bake in moderate oven (about 350 degrees) for 20-25 minutes.
Upon removal from oven, sprinkle top with chocolate chips, and let stand for about 5 minutes. Spread melted chocolate over top.
For topping, combine powdered sugar, peanut butter, and enough milk to make a thin icing. Drizzle over melted chocolate in pan. Cut chocolate peanut butter bars into squares or "fingers." Serve and enjoy!
Serving: 1Servings | Calories: 382kcal | Carbohydrates: 45g | Protein: 7g | Fat: 21g | Saturated Fat: 10g | Polyunsaturated Fat: 3g | Monounsaturated Fat: 7g | Trans Fat: 1g | Cholesterol: 37mg | Sodium: 232mg | Potassium: 224mg | Fiber: 3g | Sugar: 29g | Vitamin A: 274IU | Calcium: 37mg | Iron: 2mg